Preparation?Characterization And Application Of Tetracycline Magnetic Molecularly Imprinted Polymers

The tetracycline surface molecularly imprinted polymer?TC@Fe₃O₄@SiO2@MIP?was prepared by using tetracycline?TC?as template and Fe₃O₄ as carrier.TC was degradated under alkaline conditions,the product was used as tetracycline fluorescent marker?Flu-TC?.It competed the sites on TC@Fe₃O₄@SiO2@MIP with TC,thus to detect TC trace residuce in milk by magnetic molecular imprinting fluorescence immunosorbent competition adsorption method?MMIFICAM?.Fe₃O₄ nanoparticles were prepared by coprecipitation method.The silicon nanoparticles were coated on the Fe₃O₄ nanoparticles surface by hydrolysis of ethyl tetraethyl orthosilicate?TEOS?with aqueous ammonia catalysis,and the magnetic nanoparticles were activated with silanization reagent KH-570.The tetracycline was used as the template molecule,Methacrylic acid?MAA?as the functional monomer,ethylene glycol dimethacrylate?EGDMA?as the cross linking agent,2,2'-Azobis?2-methylpropionitrile??AIBN?as initiator,by surface molecular imprinting technique,to synthesize the TC@Fe₃O₄@SiO2@MIP.The morphology,structure and magnetic properties were characterized using SEM,IR,VSM,respectively.The adsorption selectivities of template molecules and the similar componds were studied.The results show that the polymer has good specific adsorption to tetracycline.The adsorption isothermal data and the dynamic adsorption data were fitted.It was found that the adsorption process between TC and TC@Fe₃O₄@SiO2@MIP follows Freundlich adsorption isothermal model and Pseudo-second order kinetics.By the adsorption experiments and Scatchard equation analysis,it was found that there are two binding sites on TC@Fe₃O₄@SiO2@MIP for tetracycline:specific and non-specific.The fluorescent marker?Flu-TC?was prepared by degradation of TC under alkaline conditions.The adsorption selectivity of Flu-TC by the TC@Fe₃O₄@SiO2@MIP was evaluated.The results showed that TC@Fe₃O₄@SiO2@MIP has some certain selectivity for fluorescent marker.Thus,MMIFICAM for detection the TC trace residuce in milk can be established.The milk were pre-treated with Oasis HLB solid-phase extraction column,the Flu-TC was used as fluorescence marker,and the MMIIAM for detection the TC trace residue in milk was established.The lowest limit detection of TC is 10ppm.The absolute extraction rate of the method is 68%.The linear equation was Y=-11.207x+24.197?R2=0.9896?,in the concentration range O.Olmg/L-1mg/L;Y=-0.4054x+14.124?R2=0.9782?in the concentration range lmg/L-40mg/L,The average recoveries was between 76.32%and 89.92%,RSD were less than 10%.The method couples the rapid separation of magnetic materials,the specific recognition of"antibody" of molecularly imprinted materials and the low detection limit of fluorescence immunoassay.It provides a new idea for rapid determination of trace tetracycline residue in milk.